If, originally we thought we could reuse a credit line deed of trust, and therefore disclosed minimal fees in the title work for this, but later have found out from our attorney that we cannot reuse the credit line deed of trust, would this be a valid change in circumstance that we could reissue the GFE?

In my opinion, this would not be a valid COC circumstance. If there is any question pertaining to something of this nature, you should disclose 'worst case'. IMHO, this is a lender error.

I agree RRJoker.